Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754066Ab3DUS4Q (ORCPT ); Sun, 21 Apr 2013 14:56:16 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:60343 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754014Ab3DUS4O (ORCPT ); Sun, 21 Apr 2013 14:56:14 -0400 Date: Sun, 21 Apr 2013 11:56:09 -0700 From: "Paul E. McKenney" To: Borislav Petkov Cc: x86-ml , lkml , tiwai@suse.de Subject: Re: irq 16: nobody cared Message-ID: <20130421185609.GD3509@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130420185330.GA4654@pd.tnic> <20130420235206.GA3509@linux.vnet.ibm.com> <20130421103403.GA4594@pd.tnic> <20130421163002.GB3509@linux.vnet.ibm.com> <20130421165653.GA4623@pd.tnic> <20130421181035.GC4559@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130421181035.GC4559@pd.tnic> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13042118-2398-0000-0000-0000138DB001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3007 Lines: 95 On Sun, Apr 21, 2013 at 08:10:35PM +0200, Borislav Petkov wrote: > On Sun, Apr 21, 2013 at 06:56:54PM +0200, Borislav Petkov wrote: > > Ok, let me try to disable the soundcard in the BIOS. > > Ok, there's no warning message anymore but maybe a dozen of seconds > delay before the machine is actually powered off. That is not so good... > "... > ACPI: Preparing to enter system sleep state S5 > [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored > > ... > " > > So could it be that some RCU cleanup stuff is going on during that time? CONFIG_RCU_FAST_NO_HZ will definitely change the timing, for example, increasing grace-period durations by up to a factor of four. One way to figure out if this is the problem would be to either (1) apply the following patch (assuming you have no more than a few tens of CPUs) or (2) setting the sysfs rcutree.rcu_expedited variable to 1 just before suspending the system. Either approach will force RCU to always use the faster expedited grace periods for synchronize_rcu() and friends. They will -not- help if someone has open-coded synchronize_rcu() in terms of call_rcu(), though. > I mean, the issue is not that big of a deal - when the box resumes, the > sound card works just fine so... Fair point. perhaps we should wait for Takashi to weigh in. Thanx, Paul > Thanks. > > -- > Regards/Gruss, > Boris. > > Sent from a fat crate under my desk. Formatting is fine. > -- ------------------------------------------------------------------------ rcu: Not for inclusion: Force expedited grace periods Signed-off-by: Paul E. McKenney diff --git a/kernel/rcutree.c b/kernel/rcutree.c index a9610d1..55c5ef6 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -2420,7 +2420,7 @@ void synchronize_sched(void) "Illegal synchronize_sched() in RCU-sched read-side critical section"); if (rcu_blocking_is_gp()) return; - if (rcu_expedited) + if (1) synchronize_sched_expedited(); else wait_rcu_gp(call_rcu_sched); @@ -2447,7 +2447,7 @@ void synchronize_rcu_bh(void) "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section"); if (rcu_blocking_is_gp()) return; - if (rcu_expedited) + if (1) synchronize_rcu_bh_expedited(); else wait_rcu_gp(call_rcu_bh); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 46b93b0..190a199 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -711,7 +711,7 @@ void synchronize_rcu(void) "Illegal synchronize_rcu() in RCU read-side critical section"); if (!rcu_scheduler_active) return; - if (rcu_expedited) + if (1) synchronize_rcu_expedited(); else wait_rcu_gp(call_rcu); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/